I've never quite bought in to the idea that the MCU has consistently weak villains, but given how much David Tennant's Killgrave outshines most of them, it's easy to see how you'd think that. The folks at Marvel/Netflix seem to agree, because he appears to be coming back in some form for Jessica Jones season two.
Entertainment Weekly snapped this official set photo of The Purple Man alongside Krysten Ritter's Jessica, which means his inclusion isn't exactly a reveal. If you're still trying to avoid spoilers for season one though, you should probably turn back now:
Jessica Killed this walking embodiment of entitlement and toxic masculinity last season, and while one might assume he could show up as some sort of PTSD flashback, EW also had this to say:
Marvel is keeping specific details of Tennant’s involvement under wraps
That doesn't exactly confirm or deny anything, and for all we know it could've just been one day of work and the picture was released to fuel speculation. Then again, the "realistic" world of the Netflix shows has dragons now and Elektra is coming back from the dead for The Defenders. Anything is possible.
Jessica Jones, by far the best one of these things, returns in 2018.